1. Field of the Invention
The present invention relates to an intermediate compound useful for synthesizing cephamycin compounds useful as antibacterial agents and to a process for production of the same. More particularly, the present invention provides 7.beta.-substituted-3-lower alkanoylacetoxymethyl-7.alpha.-methoxy-3-cephem-4-carboxylic acid represented by following general formula (I): ##STR2## wherein R.sup.1 represents a lower alkyl group and R.sup.2 represents an amino group which may be protected, and a salt thereof.
The present invention also provides a process for producing the compound shown by general formula (I) which comprises culturing bacteria which belong to the genus Streptomyces and are capable of producing a cephamycin compound represented by following general formula (II): ##STR3## wherein R.sup.3 represents a hydrogen atom or a methoxy group and R.sup.4 represents a hydroxy group or a sulfoxy group, allowing yeast belonging to the genus Torulopsis, or esterase derived from the yeast or material containing this esterase, to act on the accumulated cephamycin compound of general formula (II) in the culture solution to form 7.beta.-(D-5-amino-5-carboxyvaleramido)-3-hydroxymethyl-7.alpha.-methoxy-3 -cephem-4-carboxylic acid (hereafter simply referred to as "oganomycin E") of following formula (III): ##STR4## or a salt thereof (fermentation production step); reacting the oganomycin compound of formula (III) (optionally with its amino group protected) with a lower alkanoylacetic acid or a reactive derivative thereof (chemical process step); and optionally removing a protective group and/or converting to or from salt form.
The compounds according to this invention are novel and there is no published report on them. A characteristic feature of the claimed compounds in terms of chemical structure resides in the fact that the lower alkanoylacetoxymethyl group is present at the 3-position of the cephalosporin ring. The compounds of the present invention can easily be prepared employing as an intermediate compound oganomycin E which can be produced in high yield by our novel fermentation process found by the present inventors et al.
2. Background of the Invention
Known methods for producing oganomycin E by fermentation methods include culturing Streptomyces chartreusis SF-1623 under aerobic conditions and harvesting the compound from the culture solution (published unexamined Japanese patent application No. 121488/1975) and culturing Streptomyces oganonensis and harvesting the compound from the culture solution (published unexamined Japanese patent application No. 43697/1982).
However, the former method gives a low yield and is unsuitable for industrial production. The latter method provides at least 1000 times the yield but the concentration of oganomycin E accumulated in the culture solution is approximately 5 mg/ml.